1. Field of the Invention
The present invention relates to a cutting machine such as a hand-held circular saw and more particularly, to a technique of disposing of chips generated during cutting operation on a workpiece.
2. Description of the Related Art
Chips generated by operation of cutting a workpiece (particularly wood) using a hand-held circular saw are carried by air flow which is caused by rotation of a blade (saw blade) cutting the workpiece and passes through the inside of a blade case that covers substantially an upper half region of the blade and are then discharged from the rear of the blade case. Part of the chips, however, fly out forward and accumulate on the upper surface of the base or the upper surface of the workpiece ahead of the base, resulting in hiding a cutting line guide on the upper surface of the base or a cutting line marked on the workpiece under the chips. In order to solve such a problem, a technique is provided for blowing away the chips by utilizing cooling air used to cool a motor. For example, Japanese laid-open patent publication No. 2007-517702 discloses a chip disposal technique in which an outlet is formed in a front region of the motor housing in the vicinity of a connection between the motor housing and the blade case, and in which air used to cool the motor is blown obliquely from above onto a cutting region (in the vicinity of a cutting point between the saw blade and the workpiece) ahead of the base.
In the circular saw, an angular plate for bevel angle adjustment in bevel cutting operation is disposed on the upper surface of the base in front of the motor housing or forward of the motor housing in the cutting direction. Therefore, in the above-described known technique, a slit for air flow is formed in the angular plate, so that cooling air discharged from the outlet passes through the slit and blows onto a cutting region ahead of the base. However, for structural reasons, a clearance exists between the front end of the blade case and the end of the angular plate, so that cooling air discharged from the outlet flows out obliquely laterally through the clearance. As a result, the amount of air which is blown through the slit toward the cutting region decreases, so that the effect of blowing away chips by cooling air is lessened. Therefore, in this point, further improvement is required.